Families with two working parents earning less than £150,000 each could be able to claim back up to £1,200 a year per child under government plans to be put out to consultation on Monday.

The online childcare voucher system, which was first announced in March, will benefit 2.5 million working families. If after the 12-week consultation the scheme is introduced, families will be able to take advantage of it from 2015.

Labour have opposed the plans, saying that they proved the government was “out of touch”, as it had already taken support away from parents.

The party's shadow minister for children and families, Sharon Hodgson, said: “Only David Cameron's government could be so out of touch that they expect families to be grateful for help with childcare in 2015 when they've already seen costs spiralling and support taken away.

“This government has hit hardworking parents. Families with two children have already lost up to £1,500 in childcare tax credit.”

Other critics have responded by saying that the scheme would penalise stay-at-home parents. About 1.2 million stay-at-home parents, most of whom are mothers, will not be eligible for the assistance.

When the voucher proposals were first announced, Prime Minister David Cameron claimed that the plans, set to cost £1.4bn, would be a “boost direct to the pockets of hard-working families”.

The system is expected to be phased in from autumn 2015, covering children under age five for the first year. The government's ambitions are for the scheme to extend to helping all children under 12.

Lynne Burnham, the secretary of Mothers At Home Matter, a group representing those who choose to raise their children full-time, told the Telegraph the proposals were wrong in principle and practice.

“Families with parents who stay at home with children are no less valuable or important than those where both parents work,” she said.